In a magnetic disk drive, the smaller the gap between the recording layer of a magnetic disk and the write/read elements of a magnetic head slider, the greater the recording density of information can be increased. For this reason, conventionally, if the flying height of the magnetic head slider is lowered, the recording density of information of the magnetic disk drive is enhanced. At the present time, the flying height of the magnetic head slider above the magnetic disk, that is, a distance from the surface of the magnetic disk to the lowest point of flying height of the magnetic head slider at the time of flying, has been reduced to about 10 nm. There is little margin for variation in the flying height for the magnetic head slider in consideration of variations in the flying height of the magnetic head slider caused by a change in temperature of the magnetic disk drive and a change in atmospheric pressure in or around the magnetic disk drive.
JP-A-2000-353370 (patent document 1) discloses a technology in which variations in the flying height of a magnetic head slider having a front pad and a rear pad can be reduced by forming a pressure control groove in a negative pressure groove on the air inflow side of the rear pad. JP-A-07-254248 (patent document 2) discloses a technology in which spherical projections are formed symmetrically in a longitudinal direction or in a lateral direction on the flat surface of an air-bearing surface to stabilize the flying height of a magnetic head slider. However, it has become difficult to secure the flying margin of the magnetic head slider by improving static flying characteristics by these measures.